The conventional lysimeter probes are provided with a tubular basic body to which a suction cup, made of porous material, e.g. of ceramics, sintered metal or the like, is affixed on the end which is turned towards the ground. The suction cup itself forms the tip of the lysimeter probe and is mostly cylindrically or conically shaped, the free end of the suction cup being conically or roundly tipped. The suction cup is fragile, whereas the basic body is mostly made of plastics. Thus, the suction cup, which is permeable to liquids and sensitive to pressure, is in danger of being destroyed upon the insertion into the ground. Also during the removal of the lysimeter prober, for instance when it is to be used again or another site, the suction cup is in danger of being destroyed. To prevent this danger it has been known to first pilot-drill with a soil auger and then to insert the lysimeter probe into this pilot-drilled hole. However, this only reduces the danger of the destruction of the porous cup, but does not completely eliminate it. Since the porous cup must have contact with the ground in order that the solution from the ground may be taken in by the lysimetric method, forces act between the ground and the suction cup. These forces are directly transferred to the basic body so that in any way suction cup and basic body are equally stressed. Taking into consideration that such a lysimeter probe has to be driven also into rather hard soils, for instance, into pebbles, it is understandable that the destruction of the suction cup is rather the rule than the exception. As a consequence of the considerable ground contact in the area of the rounded or otherwise tapered tip, the surface of the suction cup is also considerably soiled, i.e. the soil clings to the surface of the suction cup. Thus, the suction cup is no longer appropriate for measurements on other sites, not to mention that the measurement taken on a second site may be falsified as a consequence of soil from a first place of measuring clinging to the probe. Thus, it has been known either to remove the porous suction cup from the basic body or replace it with another porous suction cup.